The best genealogical practice is to add to your tree only what you have evidence for, unless you want to have a separate private tree with speculative items that need evidence. There you can add notes or comments about research progress on speculative items. Or just keep speculative items on your home computer genealogical program, also with notes and comments about research progress on questions.
There are lots of family stories that are invented, transformed from a misunderstood verbal transmission, put into a published mug-book sketch as someone's more political than genealogical viewpoint, etc. A published sketch of one of my cousins born in 1870s gets the name of his paternal-line grandfather wrong, but asserts ancestry from Jamestown in 1607 (the many intervening generations were not given in the sketch, nor was the name of the supposed ancestral settler). Blah, blah, blah.
There are jillions of instances where people are living in others' households as aunt or cousin (if in Census enumerations where relationships to head of household are given) that can take a lot of work to determine the precise nature of the relationship. Land, estate and court records can help; it is a mistake to think that just because you found a death record on the web you are "done" with the research! Maybe Mary made a will devising to her adopted daughter Helen, the property to be held in trust by her cousin Ada, and maybe both are listed in relatives' obituaries that give more detail on relationships. Putting the puzzle pieces together is real work that you can be proud of when you find answers. Maybe not in a week or a year, but when you can get to where the information may be located.